This invention relates to the field of telemetry and of two-dimensional or three-dimensional cartography.
The reference points of a plane or the acquisition of the volume of an architectural or industrial space are generally determined by surveyors using successive plotted reference points and tracing of planes from these reference points.
Plotting interior reference points encounters many obstacles. It is slow and expensive if it is only performed manually because such plotting must be performed by a skilled person, generally a surveyor. It is also time-consuming if it is performed automatically with a device because the device must record a considerable number of data (fine angle plotting laser telemetry), the computer processing of which can require many hours.
It is necessary to carry out a computer-based construction of the image once the acquisition of points has been performed. Processing of the resultant image is time consuming (photogrammetric technique), complex and indeed not very reliable because of the difficulty of automatic interpretation of the results. Moreover, if these measurements are performed by a device, the device must be positioned in an absolute reference frame to collect the measurements. The technique used by motorized theodolites such as the double plotting technique according to which the theodolite plots its own position from one measurement to the next is precise, but time consuming.
Commonly used telemeters are elapsed time telemeters which exhibit a precision of about 3 cm (1 cm on average over multiple measurements) which is not compatible with the precision required for interior plotting.
French patent FR 2,630,539 has as its object processes for performing surveys of envelope meter distances constituted of plane surfaces using a laser beam telemeter. The process of the prior art consists of creating a means for the interior plotting, for the measurement of meter distances over small distances in the building interior and associating it with a computer-assisted design program to reproduce the envelopes and constitutive elements of a room in any desired form. The telemeter is used to measure the meter distances of the polar coordinates of any cloud of points P taken on each surface constituting the envelope from the same station S1. One then calculates the position of each plane, sphere, torus, cylinder or other simple surface. Then, the intersection of all of the surfaces is taken two by two to define the edges of the volume under consideration.
Such a process is delicate to implement because it is totally automated, implying the taking into account of all of the geometric situations which might be found in the field and the implementation of complicated computer processing.
Also known is U.S. Pat. No. 5,337,149 which describes equipment enabling creation of a computer-based model of a three-dimensional object of large dimensions as the data are acquired. This equipment of the prior art comprises a measurement device, a computer containing a computer-assisted drafting program, a data transmission device and a display screen. The distance measurement device takes measurements from a stable location and which can be moved. The location of measured points is calculated in relation to the distance of the measured point and the orientation of the measurement device. The device and the process function in a manner such that the user is connected with the computer-assisted drafting program and uses the measurement device as an input device to introduce the data into the program. Thus, the user can create a complete model of the object solely by taking the physical measurements of an object or a space without any limitation of movement around the object or the space, or through the space. It also describes a portable variant comprising an inertial unit.
Such equipment can only be used in a continuous space and does not enable acquisition of irregular volumes comprising masked zones, for example, an apartment comprising multiple rooms separated by doors. Moreover, the portable variant unit only provides a differential signal, the exploitation of which requires powerful computing means and frequent recalibrations.
Also known is U.S. Pat. No. 5,247,487, which describes a system for collecting measurements in space determining the position, orientation, form and/or operational characteristics of an environment. The system comprises a data-generating device and a modeling device. The data generated can then be transformed in a CADD (computer-assisted design and drafting) model of an existing or constructed environment, or used in another manner to obtain a three-dimensional topography of the environment.
This system employs a multiplicity of beacons positioned in the room to be analyzed.
It would therefore be advantageous to resolve the drawbacks of the prior art by providing a solution that makes it possible to reduce substantially the time required for the acquisition of useful information. It would also be advantageous to provide a process and equipment making it possible to associate the person and the machine in a manner to only measure that which is necessary, thereby reducing manual interventions to a minimum and optimizing the automatable functions.
This invention relates to telemetry equipment for two-dimensional or three-dimensional mapping of a space including a movable telemetry head including a first sensor for measuring a distance to a target within the space and a second sensor for measuring a distance to a third sensor, and a fixed unit for acquiring the position of the telemetry head in a fixed reference frame within the space, the fixed unit including the third sensor, which performs the measurement of the distance between the second sensor and the third sensor.
This invention also relates to a telemetry process for two-dimensional or three-dimensional mapping of a space including remotely acquiring a position and orientation of a laser telemeter (portable unit) in a fixed reference frame of a fixed unit within the space by manual plotting with a portable tool including a sensor emitting a visible laser beam, and measuring the distance between the telemeter and the fixed unit.